1. Field of the Invention
Embodiments of the present invention generally relate to apparatus and method for monitoring and controlling temperature of semiconductor substrates during processing. More particularly, embodiments of the present invention relates to processing chamber with components having increased pyrometry visibility at low temperatures.
2. Description of the Related Art
Shrinking feature size in semiconductor devices greatly increases the need for precise processing. One factor for precise processing is uniformity, including uniformity within a substrate and among substrates. It is critical to expose a substrate or a batch of substrates to a processing environment at a uniform temperature during processing. Therefore, there is increased need to improve temperature uniformity in semiconductor processing.
At the same time, the need for effectiveness also increases as the manufacturers adjusting to the increased competition. Batch substrate processing, rather than single substrate processing, is one of the trend to achieve higher effectiveness as batch processing increases throughput. A batch processing chamber, used in a batch processing, is generally configured to house a plurality of substrates in a processing volume and process the plurality of substrates simultaneously. The plurality of substrates are generally stacked or other wise arranged with a device side exposed to a processing environment within the processing volume. Each of the plurality of substrates is exposed to a different region of the processing volume. Achieving uniformity within a batch processing chamber is a critical and usually difficult task for the manufacturers.
Many batched processes, such as for example thermal annealing, chemical vapor deposition, and atomic layer deposition, are very sensitive to temperature. Temperature uniformity is necessity within a batch of substrates, among batches, as well as across a surface of a single substrate.
Temperature uniformity is usually achieved by measuring temperatures in various locations in a batch chamber, and controlling the temperature according to measurements. Non-contact temperature measuring methods, such as pyrometry, are convenient and effective way to measure temperature of substrates or chamber components in a semiconductor processing chamber since semiconductor processes are usually performed in a controlled environment and temperature may be measured without the processing environment being contaminated, damaged or interfered.
However, pyrometry integrated in the state of the art processing chambers has difficulties measuring temperature below 500° C. because substrates and/or chamber components do not emit sufficient infrared energy to be seen by pyrometers at temperatures below 500° C.
Therefore, there is a need for apparatus and method for non-contact temperature measurement in wider temperature range.